Improved chuck for grinding crystals



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`J. S. WARNER, OF vOGDENSBURGr, NEW YORK.

.Letters Patent No. 98,820, dated January 11, 1870.

IMPROVED CHUCK FOR GRINDING- CRYSTALS.

l The Schedule referred to in these Letters Patent and making part ofthe same.

To all 'whom it may concern i Be it known that I, J. S. WARNER, ofOgdensburg,

' in the county of St. Lawrence, and State of New York,

be attached to the lathe-mandrel at the base, andl provided with aface-plate, capable of being readily attached to the edge, or the partresembling the top of .the cup, or detached therefrom. The face of `thecrystal .is ground against the side of this plate, using emery and oil,and holding it, by rst attaching it to a stick, by sealing-wax,orvotherwise, and when the face is suiliciently ground, the plate isremoved, and the edge finished inside the cup-shaped part.

' Figure l is a sectional elevation ot' the cup-shaped part, which isattached to the mandrel;

Figure 2 is a front elevation'f the same; Figure 3' is a side elevationofthe face-plate; and Figurel 4 is a section of both attached together.Similar letters of reference indicate corresponding parts.

A is lthe cup-shaped part, having a conical space,

B, of sufficient diameter and depth to receive the largest`or smallestcrystals, and to act, by its inner wall, on the edges, to reduce andfinish them, emery and oil being used, and the crystals being held onsticks,`to which they are attached by sealing-wax or.

other suitable means. This cup A is attached, at the centre ot' the baseC, to the mandrel ofa lathe, or other rotary spindle, to be rotated whenthe crystals are presented to it, as above. Y

D isthe faceplate, adapted for attachment to the part A, at the openend, and for grinding the faces of the edges of' the crystals, byholding them against the front thereof, oil and emery being used in likemanner. The crystals commonly require to be ground in both these ways infitting, and it is important to be able to -change readily from the oneto the other.

For this purpose, I have provided a flange, E, on the face-plate, whichts a short cylindrical part, F, ofthe cup, and has two radial pins G,which, together with the right-angular notches H in the edge of the cup,form bayonet connections, by which the two parts may be readilyconnected or disconnected.

' Having thus 'described my invention,

I claim as new, and desire to secure -by Letters Patentj A crystal-grinding chuck, composed of the cupshaped part Aand face-plate or diskD, the cup being arranged t'or attachment to the mandrel, and the diskdetachably connected to the cup, all substantially as specified.

The abovel specification of my invention signed by me, this 27th day ofNovember, 1869. A

` t J. S. WARNER. Witnesses:

GEO. W. MABEE, ALELF. ROBERTS.

